Stay-bolt construction



'June 1 192s. 1,586,921

F. w. SHUPERT STAY BOLT CONSTRUCT-ION I Filed June 9 1924 i F &

' FTKWE j ir Patent-ed June 1, 192%,

UITEQ STYLE-i5 FRANK W'. SHUPERT, OF SANFORD, FLOBIDAA STAY-BOLT CONSTRUCTION.

Application filed June 9, 1924- Serial No. 718,871.

The present invention relates to improvements in boiler staybolt constructions, and more specifically to an improved flexible staybolt construction for affording some elasticity between the inner and outer firebox sheets of the boiler, whose different rates or degrees of expansion cause numerous breakages of the s't-aybolts now in common use.

The primary objectof the invention is to provide a flexible staybolt construction, designed to. permit of slight relative movement, due to expansion and contraction, of the two plates which it connects, in a manner to prevent bending or shearing of the bolt.

A further object of the invention is to provide an improved mounting for the headed end of a staybolt, having a bearing member so associated with the headed end of the staybolt and with the outer surface of the wrapper or outer firebox sheet as to permit of lateral movement of the bearing member with respect to the wrapper sheet as well as movement of the shank and head of the staybolt with respect to the bearing member.

A still further object of the invention is to provide improved staybolt constructions embodying sealing caps for preventing leakage, and having. the sealing caps so formed as to permit of the inspection of the staybolts without the necessity of removing the sealing caps from the wrapper sheet.

Other objects and advantages of the invention will appear in the following detailed description, taken in connection with the accompanying drawing, forming a part of this specification, and in which draws;

Figure 1 is a fragmentary section through the fire-box portion of a boiler and showing a staybolt construction embodying my invention;

Figure 2 is a section on the line 22 of Figure 1 and looking in the direction of the arrows; and,

Figure 3 is a fragmentary section through the crown of the sealing cap, and illustrating the manner of repairing the cap after the required inspection of the stay bolt.

Referring to the drawing in detail, and wherein similar reference characters designate corresponding parts throughout the several views; A designates a fire-box portion of a boiler embodying a wrapper or outer fire-box sheet B and an inner fire-box sheet C; D a button head type of stay-. bolt; E a slidable mounting for the headed end of the staybolt, and F a cover means for enclosing the slidable mounting E and the head of the staybolt D.

The wrapper sheet B is provided with an opening 5 which is normally disposed in axial alignment with a screw threaded opening 6 provided in the inner sheet C. The opening 5 is substantially larger than the shank 7 of the staybolt D thus permitting lateral movement of the shank within the opening 5; while the screw threads-depening 6 is of a size for screw threaded. engage ment with the threaded end portion of. the

staybolt. The inner end of the staybolt may be secured to the inner sheet C in any suitable'manner. 1

'lhe staybolt D, which may be of the button head type, has the head portion 8 thereof, which is of greater diameter than the open ing 5, formed with an annular convexed inner face 9. The head 8 may be provided with a wrench receiving recess 10 to facilitate screwing the staybolt into the inner fire-box sheet G.

Referring to the slidable mounting E, the same preferably consists of a loose washer 11, provided at one side with a concavedannular seat 12, acting as a seat for the convex-portion of the head 8, and having its otherside formed fiat for surface engage ment with the outer face of the wrapper sheet B. The bore of the washer 11 is also of greater diameter than that of the shank 7 of the staybolt.

It will be seen from the dotted line shown in Figure 1, that relative movement of the mounting E and the head of the staybolt D,

consists of a hollow semispherical shell 13 having an inspection cap 14 integral with and projecting outwardly from the crown thereof- This shell, which is of a size to permit of sliding movement of the washer 11 in; any direction, is welded: asxa-ti l5 tothe outer face of thewrapper sheet 13 to provide a steam tight cover.

hen inspection in accordance with the.

Federal, State, or municipal requirements,

are to be made, the cap 14 maybe burned ofi", with a torch for permitting of the inspecto the shell as shownat 16' in Figure 3- of the drawing, thereby sealingthe cover; It is of course tobe understood that should the staybolt be found to be broken, then the Whole cover-will necessarily need to be disconnected from the wrapper sheet.

It will therefore be seen that a novel flexible staybolt' construct-ion hasbeen provided whereby all bending or shearing stresses at the inner connection ot'the staybolt will be eliminated, and'ineorporating a novel cover means whereby inspection of the bolts may be readily accomplished in an eflici'ent manner;

Changes in detail may be made without departingg"fronrv the spiritof thre invention or the-scope of the following claims; but,

I claim:

1-., Incombination? with spaced inner and outer fire-box sheets, a staybolt construction comprisinga bolt including a shank, a screw threaded portion at one end of the shank, fixed in screw threaded engagement to the inner firebox sheet, and a relatively shallow button-like head integral with the opposite end of the shank and disposed. exteriorly of the outer fire-box sheet with the shank freely movable laterallyin: an opening of said last mentioned sheet and thefacc of the head confronting the-outer sheet being convex in: shape; and a mounting for the headed end of said bolt comprising" a ring like member slidable over the face of the outer sheet and having a ooncaw'ed annular seat for the convex facesot said head.

2; A staybolt cover comprising" a one piece hollowsemi-spherical shell welded about the staybolt opening in the fire box sheet, and a relatively small hollow inspection cap formed; integral with and projecting from the crown of said shell.

FRANK W. SHUPERT; 

